Why is Jesus called the only begotten son of God?
Aren't we all children of God?

Answer by Fr. John Echert on 12/12/2012:

Only Begotten is said only of two figures in the Bible: Isaac, son of Abraham, and Jesus. Isaac prefigures Christ in many ways:

Only Begotten Son
Sacrificed by his father
Rescued from death on the third day
Sacrifice was to take place same place Christ was crucified

Jesus is Son of God by divine nature; we are sons and daughters only by spiritual adoption, when we are baptized into Christ. It is a great privilege, even beyond that of what the angels enjoy, but short of what Jesus Christ enjoys as God Himself, and divine Son.